Open end transit agitator or mixer



Sept. 18, 1956 R, W. sMlTl-l 2,763,474

OPEN END TRANSIT AGITATOR OR MIXER Filed Dec. 2l, 1953 l i za l /,f/ l 26 3e 26 3o 2 f/ I 1 o ;\4o 4 32 I3% /2 x E l 1 1*42. y' 34 Jl |l f (y V1 4?. L x H u a r"- (Z/ s O O I4 (4 W rw im, "WIM-',.fla

Plex. 2

INVENTOR.

oeem W. Smm-1 A-rToRNsY OPEN END TRANSIT AGITATOR OR MIXER Robert W. Smith, Milwaukee, Wis., Smith Company, Milwaukee, Wisconsin assignor to The T. L. Wis., a corporation of This invention relates to transit type concrete agitators and mixers and particularly to transit agitators and mixers of a simpliiied construction and reduced weight which can carry greater legal pay loads.

I have found that the sealing door generally found on transit mixers can be eliminated. The usual charging hopper (which may discharge into the so-called charging cone) may be retained in this construction but need not seat on the rotating parts, thus avoiding seats, seals, and lubrication and maintenance of the seals. The weight of the omitted door is, of course, saved and other weight savings may also be made, permitting the legal load to be correspondingly increased. While the rotating blades may handle the mix well enough to avoid spillage, concrete may spill from centrally of the blades as a result of the increased load or surge of the drum contents. I have found a simple means for controlling the spillage to return the mix to the drum and to additionally gain a desirable mixing (or agitating) action. The present structure may be used alone or in combination with the structure illustrated in my copending application Serial No. 399,198, tiled December 2l, 1953, now Patent No. 2,723,112, dated November 8, 1955, which discloses a new blade and blade cover arrangement for the rear end of the drum to reduce or eliminate leakage around the blades.

The principal object of this invention is to increase the capacity and reduce the weight of transit agitators and mixers.

Another object is to prevent spillage from centrally of the blades on an open ended transit agitator.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the single embodiment shown in the drawings, in which:

Fig. l is a rear view of a transit mixer according to ',this invention; and

Fig. 2 is a fragmentary side View partly in section of 'the agitator shown in Fig. l.

The drawings illustrate a high discharge type drum 10 rotatable about its upwardly and rearwardly inclined axis on rollers 12, 12 rotatable in brackets 14, 14 mounted on frame 16 and on a bearing at the front (not shown) of the drum. This drum is provided with a charging cone 18 at its rear end centrally of blades 20, 22. This cone is xed to and rotates with the blades and may be of the conventional type (extending into the drum a short distance) such as shown in U. S. Patent No. 2,563,963 or may be modified as shown in said copending application Serial No. 399,198 to reduce or eliminate leakage around the blades even when the drum is filled above its rated capacity. The drum is rotated in one direction (see arrow) when charging or agitating the load and the direction of rotation is reversed to discharge the load. If the drum is not charged to excess the blades tend to prevent spillage when the drum is rotated in the mixing direction. Thus, as concrete starts to leak rearwardly .UnitedStates Patent V:O

past a blade the next blade tends to pick up the spillage and return it to the mixer. If the cone and blades are modilied as shown in said copending application the drum capacity may be increased without spillage around the blades.

A charging hopper 24 is hung on arms 26, 26 rotatable about the axis of the shaft 28 supported by the inverted Ushaped frame member 30 as hand wheel 32 is rotated to actuate crank 34 and arm 36. This mechanism is similar to that shown in Rockburg Patent No. 2,563,963 and serves to move the charging hopper to and from the charging position shown. It will be noted that the annular plate 38 covers the rear end of cone 18 but does not seat thereon. While the hopper does extend into the cone slightly, inspection of the drawings will demonstrate that mix may leak past the hopper and plate 38. The leakage or spillage would tend to fall on the roadway and to prevent this I provide the simple dellector 40 which is generally in the form of a segment of a hollow frustum of a cone. The delector 40 gathers th-e spilled concrete and guides it forwardly into the path of the blades when the drum is rotated in the mixing direction. Thus the spilled mix is merely reintroduced to the drum. It will be noted that this structure prevents the mix from getting "pocketed in the cone and forces the mixing to take place along the drum axis, particularly at the rear end of the drum where end-to-end mixing as well as the usual spiral bladeinduced mixing occurs.

When it is desired to discharge the drum contents the charging hopper 24 is swung on arms 26, 26 to move clear of the rear end of the drum. The drum rotation is now reversed and the concrete is discharged in the well-known manner into collector chutes 42, 42 which discharge into the distributing spout 44 which may be mounted in any desired manner.

Instead of mounting the hopper for swinging movement as shown, the hopper may be fixed in place (in the charging position). In such a case the discharge operation is not impaired since the space between the cone and the drum is open. The stationary mounting is advantageous where cost and weight must be kept to an absolute minimum but has the disadvantage of preventing inspection of the drum contents during mixing.

From the above it will be apparent that I have eliminated the sealing door and bearing which usually form a part of the charging hopper assembly without incurring uncontrolled leakage or spillage of concrete. In addition to eliminating the initial cost of these parts the maintenance of the parts has been eliminated. This has been accomplished without sacricing mixing action or capacity. The structure shown retains the charging hopper which ailords a simple, fast charging method. This invention may be employed with a hatch loading drum, if desired. In this case the charging hopper would be elim inated and the deector could be fixed on the frame. In this case the deector would, of course, include a vertical portion as well as the segment of a frustum of a cone. The use of the deflector to handle the spillage centrally of the drum permits the drum capacity to be increased above normal for the given drum size. Such increased capacity may require some modication of the cone and blades (such as shown in said copending application Serial No. 399,198) to avoid spillage around the blades. The present invention is useful alone or in combination with the disclosure in said copending application.

Changes in the structure shown in the drawings will occur to those skilled in the art. Accordingly, I desire this invention to be limited only by the scope of the claims.

I claim:

1. A transit type concrete agitator or mixer compriswhen a frame@ rotatably-mounted on the frameior rotation about its axis and having its rear end open, a plurality of spiral blades arranged on the interiorof the drum to move the drum contents forwardly of the drum when ,rotated inloneldirection and rearwardly when rotated inthe opposite direction, a generally frusto conical .rotation about kits axis and having its rear end open, a

plurality o fspiral blades arranged on the interior of the (drum to move the drum contents forwardly of the drum M .rotated in one direction and rearwardly when retated in theopposite direction, a generally frusto conical member ixed in the 11e/arend of the drum in contact with` the blades, ya Icharging hopper assembly swingably mounted on said .frame Afor movement to and from said member for charging and discharging, the space between said member and said drumremaining exposed at all times, and deilec'tor means carried on said hopper assembly for decting spillage from centrally of said member into said space lwherebythfeblades move the spillage forwardly when the drum isrotated in s aid one direction.

3Q A mixer according to claim 2 in which said deector means is positioned on the lower portion of said assembly and comprises atplate generally in the form of a segment of a frusturn of a' cone.

4. A transit type concrete agitator or mixer comprising, a frame, a drum rotatably mounted on the frame 4 for rotation about its axis and'having its rear end open at all times, a plurality of spiral blades arranged on the interior of the" drumk and operative to move the drum contents forwardly in the drum when the drum is rotated in the mixing direction and to move the contents rearwardly when the drum rotation is reversed, the drum contents tending to spill from the drum from centrally of the blades at the open rear end of the drum, and detlector means atithe rear end ofthe drum operative to receive spillage from the space centrally of the blades 'and conduct thc spillage to the blade ends at the rear end of the drum whereby the blades move said spillage `forwardly when the drum rotates in the mixing direction.

5. A n agitator according Vto Vclaim 4 including a generally frusto conical member positioned centrally of the blades at the open rear end of the drum, said dcector means receiving spillage from centrally of the member and conducting the spillage to the space between the member and the drum.

6. An agitator according to claim 5 in which the de ector means is carried by a hopper assembly swingably mounted on said frame and adapted to move `into a charg ing position in which the hopper discharges centrally of said member7 said assembly being out of contact `with aid member at all times.

References Cited in the file of this patent UNITED STATES PATENTS 2,254,639 Andrae T Sept. 2, 1941 FOREIGN PATENTS 532,913 Great Britain 4. Feb. 3, 1941 

